In this paper, we discuss the role of a diverse set of policies aimed at regulating the number and age structure of elections on the size and age structure of five European Academies of Sciences, namely the Austrian, Berlin-Brandenburg, Russian and Norwegian academies and the Royal Society. We show the recent pace of ageing and the degree of variation in policies across them and discuss the implications of different policies across these academies, regulating the number of elections and influencing their age structure. We illustrate the potential effect of different election regimes (fixed vs. linked) and age structures of election (younger vs. older) by contrasting the steady-state and transient dynamics of different projections of Full Members in each academy into 2070 and measuring the size and agecompositional effect of changing a given policy relative to a status quo policy scenario. Our findings suggest that academies with linked intake (i.e., where the size of the academy below a certain age is fixed and the number of elections is set to the number of members becoming that age) may be a more efficient approach to curb growth without suffering any ageing tradeoffs relative to the faster growth of academies electing a fixed number of members per year. We further note that academies need to take into consideration their current age structure before enacting this type of intake regime as the potential of (negative) momentum could be sizable.